If you don’t know Lua, it’s quite close to JavaScript in the sense that it’s a prototype based language and you can therefore write code that is Object Oriented.

Ruby being a full OO and richer language, you can organize your code differently and write more of your complex logic in a scriptable language. One could even potentially leverage the language to create its own Domain Specific Language in pure Ruby and create a “Rails like” experience within its application.

Still, I'd like a lawyer to ELI5 it for me. I'm mainly concerned about being able to claim ownership if I try to sell it, and avoiding a legal battle in a situation where the company tanks and starts liquidating its assets.

Congratulations, you're in a field where you can actually demonstrate what you're capable of. Got web dev skills? Build a website. Put the code on GitHub. Got IT skills? Host that website on AWS, or Linode, or wherever. Proud of something clever, cool, or just professional that you did with the site or the hosting? Write about it.

Also, it doesn't really matter how 'cool' your project is, it only has to be interesting enough to keep you motivated.

Seems like it would be preferable to load from your x-ly backups. The data will still be pretty recent, you won't be burdening your production DB, and you'll constantly be verifying that your backups work. win, win, win?